Sleep apnoea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. People with untreated sleep apnoea stop breathing repeatedly during their sleep, sometimes hundreds of times. But frequent, loud snoring may be a sign of sleep apnoea, a common and potentially serious disorder in which breathing repeatedly stops and starts as you sleep. As a consequence, you spend more time in light sleep and less time in the deep, restorative sleep you need to be energetic, mentally sharp, and productive the next day.